Studies collected by the Hydraulic Institute and Europump* reveal that pumping systems account for nearly 20% of the world’s electricity energy demand and from 25 – 50% of energy usage in certain industrial plant operations. This highlights the significant potential that exists to cut a company’s running costs and put a dent in its carbon footprint too by maintaining or improving pump efficiency.
There are several ways to improve the energy efficiency of an industrial pump and the application of a protective coating is one of easiest and most effective. This is typically a ceramic reinforced epoxy that can extend the life of new pump components and restore the worn surface of old ones. They create a sacrificial and renewable working surface, protecting the structural integrity of the original substrate.
Castings impellers and volutes all wear due to corrosion, erosion, cavitation and mechanical damage but all these outcomes can be significantly delayed or prevented with the application of a protective coating. The time it takes to apply is much lower than other remedial methods, such an installation overhaul and impeller trimming and it also achieves the shortest return on investment, typically 4 – 12 months.
30% energy reduction
A UK automotive manufacturer provides an excellent illustration of what can be achieved. To demonstrate potential gains in pump energy costs a 22kW ELPO pump, used for handling process water, was selected for analysis and it was found to be under-performing by a minimum of 30% against the manufacturer’s original test data.
The unit was then dismantled and all components examined for wear. The pump was heavily corroded and pump impeller worn, burred and imbalanced. The mechanical seal had seized and the pump was out of alignment with the motor. The volute was cut-water worn, the bearings showed evidence of fretting and corrosion and the motor was not inverter rated.
All components that required coating were first steam cleaned to remove any residue and salts and then bead blasted to achieve a surface roughness of 75 microns. LOCTITE® 7515 was used to pre-treat the substrates to prevent corrosion and improve adhesion between the metal parts and the polymer composite coating.
Next, LOCTITE 7177 was applied as a ‘hold coat’ to smooth the surface imperfections and provide a key for the thicker layers required to return the pump to its original dimensions. A ‘build coat of LOCTITE 7226 was then used to replace many years of wear a create tough surface, resistant to future wear. This was followed by another coat of LOCTITE 7177 to achieve a finish that would reduce friction within the pump and improve its energy efficiency.
The pump was then fitted with new bearings and both oil and mechanical seals. The impeller was dynamically balanced, the pump re-assembled and a new 22kW high efficiency motor fitted. Motor and pump were finally installed on the bedplate and laser aligned.
The second performance test was then conducted and the results were outstanding. The remedial work had restored the pump to original specification, increasing its efficiency by 30%. The cost of the repair amounted to £5,542. But offsetting this, in the first year alone, was an estimated energy reduction of £3,936. This was calculated at £0.08/kWh at 12 hours per day with an 80% load.
The ‘before’ and ‘after’ analysis from other manufacturing companies confirm similar findings. One reported a 19.9% energy efficiency increase with 4.55 months payback and a carbon emission saving of 10.2 tons per year and another a 12.67% energy efficiency boost, a 5.11 months payback time and carbon savings of 49.5 tons per year.
Ceramic reinforced epoxy coatings are available in a choice of grade for fine particles through to coarse and also specific products for pure chemical attack, corrosion and high impact.
For more information on the LOCTITE® range and advice on surface treatments in general, please visit our website:
www.henkel-adhesives.com
